Presently, traditional mid-range storage products may usually use a dual-controller architecture. For example, VNX series product manufactured by the EMC Corporation® consists of two controllers, known as Storage Processors (SPs).
Generally, in order to enlarge capacity of a product and improve performance of the product, multi-controllers may be introduced into mid-range storage products. However, designing and manufacturing a storage device with multi-controllers directly results in high cost; while, existing dual-controller storage products may need to be replaced, which causes waste of resources.